The present invention relates to locating an opaque region in a chest X-ray radiograph, and more particularly, to locating an opaque region representing the heart in a chest X-ray radiograph, for nodule detection in the heart region.
Nodules are small masses of tissue, which can form on various organs in the human body, such as the lungs. Lung nodule detection can be used for advance cancer screening. Accordingly, computer implemented methods for automatic nodule detection methods have been developed to detect nodules in chest X-ray radiographs. Such automatic nodule detection methods determine locations in a chest X-ray radiograph at which there is a high probability that a nodule exists.
In chest X-ray radiographs, the heart appears as an opaque region with different image characteristics from the lung regions. Since the heart region has different image characteristics from the lung regions, the heart region should be processed using a different nodule detection method than the lung regions. However, in order to process the heart region using a specialized nodule detection method, it is first necessary to segment, or determine a boundary of, the heart region in the chest x-ray radiograph. Accordingly, a method for segmenting an opaque region representing the heart in a chest X-ray radiograph is needed.